Epiphyte habitats in an old conifer forest in Western Washington, USA

Old conifer forests in the Pacific Northwest have a wide range of microhabi tats induced by canopy structure and substrate characteristics. We used the Wind River Canopy Crane to sample lichens and bryophytes throughout the sp ectrum of habitats available to epiphytes. Of the 111 species found in 72 s ample units, 97 were lichens and 14 were bryophytes. Epiphyte communities s howed marked variation with respect to height in the canopy: bark vs. wood, degree of sheltering, and stein diameter. Of these factors, height in the canopy was most strongly related to epiphyte communities. Furthermore, the top two meters of the tallest trees hosted a diverse assemblage of both rar e species (Tholurna dissimilis) and weedy, nitrophilous species (Candelaria concolor, Hypogymnia tubulosa, Parmelia sulcata), presumably induced by bi rds delivering lichen propagules and nutrients. Ten species were more frequ ent on bare wood than bark, including Ophioparma rubricosa, Letharia vulpin a, Placynthiella spp., Ptychographa xylographoides, Trapeliopsis flexuosa, and Xylographa parallela. Species richness was highly variable, evert withi n habitats. The only factor found related to species richness was height in the canopy: the middle and upper layers each having about twice the specie s per sample unit as lower in the canopy.